Increased phosphorylation of receptor protein-tyrosine kinases has been implicated in different carcinomas. In these cancers the degree of amplification appears to correlate with the prognosis: the greater the amplification the worse the prognosis. What is unclear is whether overall kinase amplification or the levels of activated kinase provides the better prognostic indicator. The major difficulty is the ability to specifically measure activated kinases. It is proposed in this Phase I study to develop a two-site immunoassay to specifically measure the activated receptor kinase. SH2 domain fusion proteins from specific signal transduction proteins will be used to specifically capture the activated kinase and then the amount of captured kinase will be measured using a monoclonal antibody to the receptor kinase as the reporter. Such an assay will be of great use to the individual researcher interested in evaluating the role played by activated receptor kinases specifically. In Phase II the prognostic value of such a measurement will be evaluated by screening different human tumors and correlating the data with other, independent prognostic indicators. The ultimate goal of these studies will be to provide a tool to allow earlier diagnosis and better management of the cancer patient.